1. Field of the Invention
The present invention relates to a method of producing N-vanillyl fatty acid amides other than capsaicin, and particularly producing capsaicin analogues having a non-pungent-taste, from capsaicin, which is a component contained in red peppers that has a pungent taste.
The present invention also relates to a method of producing fats and oils containing capsaicin analogues with a non-pungent-taste.
2. Description of Related Art
The major pungent components of red peppers, which are widely used as a spice, include capsaicin (8-methyl-N-vanillyl-6-nonenamide) and dihydrocapsaicin (8-methyl-N-vanillyl-nonanamide), which are N-vanillyl fatty acid amides having 10 carbon atoms in their acyl group (hereinafter, also referred to as "capsaicins", inclusive of dihydrocapsaicin).
Capsaicins are known to not only give a strong pungent-taste but also have various effects useful to living organisms such as an appetite promoting effect, a vasodilating/vasoconstricting effect, a salivation stimulating effect, a gastric acid secretion stimulating effect, an intestinal peristalsis stimulating effect, a circulatory cholesterol level reducing effect, an energy metabolism enhancing effect, a bioactive peptide release stimulating effect and the like.
In particular, explanation of its energy metabolism stimulating effect has recently been made on a molecular basis and the following facts have been revealed. That is, capsaicin stimulates lipolysis in white adipose tissue by stimulating secretion of catecholamine from the adrenal gland and also stimulates thermogenesis in brown adipose tissue. Consequently, accumulated body fat is reduced and the serum trigliceride level is lowered.
Therefore, it would be considered advisable to take capsaicins in order to prevent or remedy obesity. However, the strong pungent-taste of capsaicin prevents its continual intake in amounts which are effective.
Accordingly, research has been made to find substances from among N-vanillyl fatty acid amides similar in chemical structure to the above-described capsaicins which have useful activities similar to the physiological activities of capsaicins without pungent-taste as strong as capsaicins. As a result, it has been confirmed that of the N-vanillyl fatty acid amides, the pungent taste peaks in those whose straight chain moiety has a carbon number of 9 and then decreases with an increase in the carbon number (with a carbon number of 11, the pungent-taste becomes weak, with a carbon number of 12, substantially non-pungent-taste is sensed, and with a carbon number of 14 or more, there is no pungent-taste) and that the catecholamine secreting effect does not change substantially with carbon numbers of 9 to 20 [Life Sciences, Vol. 54, pp. 369-374].
Discovery of capsaicin analogues with a weak pungent-taste suggests the possibility that the above-described various useful effects of capsaicin analogues can be utilized with oral administration without being obstructed by a pungent-taste.
A plant that contains abundant N-vanillyl fatty acid amides having useful bioactivities similar to those of capsaicins with substantially no pungent-taste (hereafter, referred to as "non-hot capsaicin analogues") has not been found, and, hence, application of such non-hot capsaicin analogues in the food industry would require synthesized one. The N-vanillyl fatty acid amides used in the above-described investigation of capsaicin analogues were synthesized from vanillylamine and a fatty acid chloride. However, any other production method is desirable even if the yield is somewhat poor, because acid chlorides are expensive and difficult to handle.
An object of the present invention is therefore to provide a method of producing capsaicin analogues (particularly non-hot capsaicin analogues) from a starting material other than acid chlorides.
Another object of the present invention is to enable production of capsaicin analogues (particularly non-hot capsaicin analogues) by an enzymatic reaction.
Still another object of the present invention is to provide a method of producing a non-hot capsaicin analogue from capsaicins.
Yet another object of the present invention is to provide edible fats and oils containing non-hot capsaicin analogues.